Tension device for sewing-machines



(MbdeL) HOLDEN, Jr. TENSION DEVICE FOR SEWING- MACHINES N0.-277,281. Patented May 8,1883.'-

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- UNITED STATES PATENT VUFFICE.

HIRAM HOLDEN, .13., 0F SPENCER, MASSACHUSETTS.

TENSION DEVICE FOR SEWING-MACHINES SPECIFICATION forming part of Letters Patent No. 277,281, dated May 8, 1883, Application filed September 15, 1882. (ModeL) To all whom it may concern:

Be it known that I, HIRAM HOLDEN, Jr., of

Spencer, in the county of \Vorcester and State.

and dry thread sewing-machines, and have for their object to insure the tightening of the thread in the work, and to prevent cutting or breaking of the thread.

The invention consists in devices fitted to actautomaticallyin drawingand tighteningthe' thread, as hereinafter described and claimed.

Reference is to be had to the accompanying drawings, forming part of this specification, in which similar letters of reference indicate corresponding parts in all the figures.

Figure l is a side elevation of the improved tension devices as applied for using a waxthread. Fig. 2 is a similar view, showing the device as applied for using a dry thread. Fig. 3 is a face view of the tension mechanism. Fig. 4 is a detailed view of the slotted stud, within which one end of the take-up arm is guided.

A is the arm of the machine. a is the awl-. bar; b, the needle-bar; c, the presser-foot; d, thread-guide; e, cast-oft bar, and f wax-dish.

The tension devices are carried by a plate, g, that is formed for attachment to the 'arm of the machine in either of the positions shown.

It is the tension-wheel on a stud-post, t, that carries a washer and spiral spring, wit, and thumb-nut Z for adjusting the tension of the spring.

on is a spring take-up arm,.formed with an eye at its outer end, and coiled at its inner end around a stud, n, which has a set-nut, 0.

p is a guide-pin, and g is a guide-eye on the plate 9.

1' is a stud or post on the plate, carrying a regulating-screw, s, that limits the backward movement of the arm m, the stud being slotted to allow the arm to bear on the screw, and t is a set-nut on the screw 8.

In threading the tension for wax-thread machines, the thread passes, as shown in Fig. 1, from the wax-dish f througha guide,'u, fastened on stud-post i, thence to and around tendrawn from tension-wheel h.

sion-wheel h to pin 1), through eye on the end otspring-arm m, and thence through guide-eye q to the thread-guide d and needle. thread,the thread passes,asin Fig. 2, from spool to guide a, fastened on stud-post i, thence to and around tension-wheel h to pin 19, through eye on the end of spring-arm m, and thence through guide-eye q to thread-controller y and top of needle-bar, and thence to bottom of needle-bar and needle, as shown in drawings. The tension of wheel h is regulated by turning thumb-nut l, and the take-up spring'm is adjusted by the stud n, as required, to throw spring-arm back to screw 3, and fixed in place by not 0. The turning inward or outward of the screw .9 limits theamouut of thread taken up by the arm m, while its position of adjustment is fixed by the nut t.

In operation on wax-thread machines, as the needle descends it takes the thread and draws it down through the work and plate to the extent required to form the loop and cast it from the needle. ward and thethread drawn from tension-wheel h. Then, as the needle ascends to take the thread, the spring-arm m moving backward to screw 8, the thread is not drawn back with the needle, but a loop is left for the cast'off to hold until the needle again descends. In drythread machines, as the needle-bar rises the spring-arm m is drawn forward and the thread Then, as the needle descends, the spring-arm or moves backward to the screw e and leaves sufficient thread to form the loop for the'shuttle. The loop is left of the same length at every movement. Tight stitches are thus insured, and there is no risk of breaking the thread.

The center surface of tensionwheel It is roughened or double-cut, so that it is impossible for the thread to slip around the wheel, thus getting all the friction that is produced by thumb-nut l.

Having thus fully described my invention,I claim as new'and desire to secure by Letters Patent-- l. The combination, with the tension-wheel h and the plate g, having the slotted stud 0', provided with the adjusting-screw s t, of the spring take-up arm or, the said arm being arranged to move in the slot of said stud and to For dry The spring-arm mis drawn for receive the action of the screw 8, substantially nut, 0, substantially as and for the purpose set as and for the purpose set forth. forth.

2. The combination with the tension-wheel h and the plate g, ha ving the slotted stud r, 'HIRAM HOLDEN 5 provided with the adjusting-screw s t, of the \Vitnesses:

spring take-up arm on and the stud n, to which CHENEY P. PROUTY, the said arm is attached, and which has a set-' ROSWELL O. HOLDEN. 

